Problem: Khan.scratchpad.disable(); Ben sells magazine subscriptions and earns $$10$ for every new subscriber he signs up. Ben also earns a $$23$ weekly bonus regardless of how many magazine subscriptions he sells. If Ben wants to earn at least $$49$ this week, what is the minimum number of subscriptions he needs to sell?
Solution: To solve this, let's set up an expression to show how much money Ben will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Ben wants to make at least $$49$ this week, we can turn this into an inequality. Amount earned this week $\geq $49$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $49$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $10 + $23 \geq $49$ $ x \cdot $10 \geq $49 - $23 $ $ x \cdot $10 \geq $26 $ $x \geq \dfrac{26}{10} \approx 2.60$ Since Ben cannot sell parts of subscriptions, we round $2.60$ up to $3$ Ben must sell at least 3 subscriptions this week.